1. Field of the Invention
The embodiments of the invention generally relate to flip-chip assemblies and, more particularly, to a lead-free flip-chip assembly with an organic chip carrier that incorporates mushroom-plated solder resist openings.
2. Description of the Related Art
A flip-chip assembly (i.e., a flip-chip package) is an integrated circuit device (e.g., a semiconductor chip, a die, etc.) mounted on an organic laminate substrate (e.g., a chip carrier) by C4 (i.e., controlled collapsed chip connection) attachment. Typically, such assemblies are formed by forming solder bumps on an array of conductive pads on the active surface of the integrated circuit device. The device is then “flipped” and positioned such that the device solder bumps are located adjacent to corresponding solder pads within solder resist openings on an organic laminate substrate. Solder paste within the solder resist openings on the substrate temporarily secures the solder bumps in place. Then, a reflow process is performed to create solder joints that both electrically and mechanically connect the integrated circuit device to the substrate. Conventionally, eutectic leaded solder (Pb-63% Sn) has been used to form the solder joints in flip-chip assemblies. Recently, however, government regulations around the world are requiring lead (Pb)-free electronics components. Thus, there is a need in the art for a flip-chip assembly that incorporates a Pb-free solder.